Fold rear-view mirror assemblies for motor vehicles are driven through an electric motor between, for example, non-driving and driving positions. An electric motor is usually fitted inside a mirror housing which in turn also accommodates a mirror pane therein. As the electric motor is actuated, the mirror housing rotates around a mirror base or fixed part that is attached to a motor vehicle, usually to a motor vehicle body. The mirror housing can be thus positioned in at least the above mentioned two stable positions, namely, the non-driving and driving positions, corresponding to park and driving positions, respectively. A compression spring is usually fitted to act between the mirror housing and the mirror base or fixed part.
The mirror base or fixed part is provided with teeth adapted for cooperating with corresponding teeth formed in the mirror housing when the latter is rotated. Both the teeth in the mirror base and the teeth in the mirror housing define inclined planes which, in cooperation with the above-mentioned compression spring, provide a mechanical resistance against an inadvertent folding of the mirror housing relative to the mirror base between the at least two stable positions, namely the above mentioned non-driving and driving positions. For example, during travelling of the vehicle, where the mirror housing is positioned in the driving position to provide the driver a substantially rearward field of view, an inadvertent folding from the driving position towards the non-driving position may occur due to, for example, wind conditions.
When the electric motor does not work, or when a failure in the power supply occurs, and the user wishes to move the rear-view mirror housing into the driving position, a torque has to be applied by the user manually to the mirror housing so as to overcome interlocking of the teeth. The torque that is manually applied by the user is usually higher than the torque that is applied by the electric motor.
When the mirror housing is actuated manually relative to the mirror base around the mirror rotation axis, the teeth of the mirror base and the teeth of the mirror housing move relative to each other. During such relative movement, the respective inclined planes of the teeth cause the mirror housing to be raised or lowered relative to the mirror base depending on the direction of rotation of the mirror housing and the mirror base.
Downward movement of the mirror housing relative to the mirror base as it is rotated manually causes the mirror housing to move towards the mirror base compressing the compression spring. In this movement of the mirror housing towards the mirror base, the compression spring opposes rotation of the mirror housing for determining its relative angular positions. Upward movement of the mirror housing relative to the mirror base as it is rotated manually in the opposite direction causes the mirror housing to move away from the mirror base releasing the compression spring. The above configuration of teeth and inclined planes also define the above mentioned predefined driving and non-driving positions of the mirror housing.
One example of the above fold rear-view mirror assemblies is disclosed in U.S. Publication No. 2007035862 (“the '862 publication). The rear-view mirror assembly taught in the '862 publication comprises a hinge actuator with a base plate and a mirror support with cooperating stops. A coupling ring is arranged that can cooperate with the mirror support via a first set of cooperating stops, and can cooperate with the base plate via a second set of cooperating stops, such that in the first angle of the coupling ring, the spring force is transmitted, through cooperation of the first set of stops, and in the second angle, the spring force, through cooperation of the second set of stops, is transmitted to the base plate.
It however occurs that when the mirror housing is actuated manually, for example, when a failure of the electric motor for driving the rear-view mirror assembly occurs, or even if the user merely desires to drive the mirror housing manually, the above mentioned predefined driving and non-driving positions of the mirror housing may not well be achieved, since the teeth of the mirror base and the mirror housing have been moved relative to each other. This may result in that the mirror pane may not be positioned properly in the driving position to drive a motor vehicle.
International Publication No. WO2012047104 (“the '104 publication”) relates to rear view mirror assembly for a vehicle comprising an adjustment instrument than includes a housing that is pivotally adjustable between a park position, a drive position and a fold-over position with respect to a base. The adjustment instrument further comprises an electrical drive unit provided in the housing, and a drive ring for coupling with the electrical drive unit.
Such a rear-view mirror assembly is made of a number of components which interact with one another in order to perform manual and powered driving of the assembly and also to lock the mirror housing in a given position. However, the rear-view mirror assembly described in the '104 publication has the disadvantage that if a given component is removed, the mirror assembly does not work, both in manual and powered mode, and cannot be driven into the locked position in drive position.